Wireless architecture for 60ghz

ABSTRACT

A device has an RF mixer, an IF mixer module, a single synthesizer, a frequency divider, a single side band mixer and a frequency quadrupler. The single synthesizer generates a signal to the IF mixer module, the frequency divider, and the single side band mixer. The single side band mixer mixes signals from the single synthesizer and the frequency divider. The frequency quadrupler receives the output of the single side band mixer. The RF mixer is coupled to the frequency quadrupler and the IF mixer module.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/948,150 filed Jul. 5, 2007.

FIELD OF THE INVENTION

The present invention relates to the field of wireless communication;more particularly, the present invention relates to a wirelesscommunication device.

BACKGROUND OF THE INVENTION

In 1998, the Digital Display Working Group (DDWG) was formed to create auniversal interface standard between computers and displays to replacethe analog VGA connection standard. The resulting standard was theDigital Visual Interface (DVI) specification, released in April 1999.There are a number of content protection schemes available. For example,HDCP and DTCP are well-known content protection schemes. HDCP wasproposed as a security component for DVI and was designed for digitalvideo monitor interfaces.

HDMI is a connection interface standard that was developed to meet theexplosive demand for high-definition audio and video. HDMI is capable ofcarrying video and audio and is backward-compatible with DVI (whichcarries only video signals). The key advantage of DVI and HDMI is thatboth of them are capable of transmitting uncompressed high-definitiondigital streams via a single cable.

HDCP is a system for protecting content being transferred over DVI andHDMI from being copied. See HDCP 1.0 for details. HDCP providesauthentication, encryption, and revocation. Specialized circuitry in theplayback device and in the display monitor encrypts video data before itis sent over. With HDCP, content is encrypted immediately before (orinside) the DVI or HDMI transmitter chip and decrypted immediately after(or inside) the DVI or HDMI receiver chip.

In addition to the encryption and decryption functions, HDCP implementsauthentication to verify that the receiving device (e.g., a display, atelevision, etc.) is licensed to receive encrypted content.Re-authentication occurs approximately every two seconds to continuouslyconfirm the security of the DVI or HDMI interface. If, at any time,re-authentication does not occur, for example by disconnecting a deviceand/or connecting an illegal recording device, the source device (e.g.,a DVD player, a set-top box, etc.) ends transmission of encryptedcontent.

While discussions of HDMI and DVI are generally focused on wiredcommunication, the use of wireless communication to transmit content hasbecome more prevalent every day. While much of the current focus is oncellular technologies and wireless networks, there has been a growinginterest in the unlicensed spectrum around 60 GHz for wireless videotransmission or very high-speed networking. More specifically, seven GHzof contiguous bandwidth has been opened for unlicensed use atmillimeter-wave frequencies around 60 GHz in the U.S. and Japan.

SUMMARY OF THE INVENTION

A device has an RF mixer, an IF mixer module, a single synthesizer, afrequency divider, a single side band mixer and a frequency quadrupler.The single synthesizer generates a signal to the IF mixer module, thefrequency divider, and the single side band mixer. The single side bandmixer mixes signals from the single synthesizer and the divider. Thefrequency quadrupler receives the output of the single side band mixer.The RF mixer is coupled to the frequency quadrupler and the IF mixermodule.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood more fully from the detaileddescription given below and from the accompanying drawings of variousembodiments of the invention, which, however, should not be taken tolimit the invention to the specific embodiments, but are for explanationand understanding only.

FIG. 1 is a block diagram of one embodiment of a communication system.

FIG. 2 is a block diagram of one embodiment of a communication device.

FIG. 3A is a block diagram of one embodiment of a transmitter device.

FIG. 3B is a block diagram of one embodiment of a receiver device.

FIG. 4 is a block diagram illustrating one embodiment of end resultmultiple radio frequency channels.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

An apparatus and method for wireless communication is disclosed. In oneembodiment, the wireless communication occurs using a wirelesstransceiver with or without an adaptive beamforming antenna. As would beapparent to one skilled in the art, the wireless communication couldoccur with a wireless receiver or transmitter. Those of ordinary skillsin the art will recognize that the generation circuit described in thewireless transceiver may be applicable to many types of wirelessnetworks such as wireless video network, wireless personal network,wireless local network among others.

In one embodiment, the wireless communication includes an additionallink, mode, or channel, for transmitting information between atransmitter and a receiver. The link may be uni-directional orbi-directional. In one embodiment, the channel is used to send antennainformation back from a receiver to a transmitter to enable thetransmitter to adapt its antenna array by steering the antenna elementsto find a path to another direction. This may be obstacle avoidance.

In one embodiment, the link is also used to transfer informationcorresponding to the content that is being transferred wirelessly (e.g.,wireless video). This information may be content protection information.For example, in one embodiment, the link is used to transfer encryptionkeys and acknowledgements of encryption keys when the transceivers aretransferring HDMI data. Thus, in one embodiment, the link transferscontrol information and content protection information.

FIG. 1 is a block diagram of one embodiment of a communication system.Referring to FIG. 1, the system comprises media receiver 100, a mediareceiver interface 102, a transmitting device 140, a receiving device141, a media player interface 113, a media player 114 and a display 115.

Media receiver 100 receives content from a source (not shown). In oneembodiment, media receiver 100 comprises a high-definition source, forexample, such as a set top box. The content may comprise basebanddigital video, such as, for example, but not limited to, contentadhering to the HDMI or DVI standards. In such a case, media receiver100 may include a transmitter (e.g., an HDMI transmitter) to forward thereceived content.

Media receiver 100 sends content 101 to transmitter device 140 via mediareceiver interface 102. In one embodiment, media receiver interface 102includes logic that converts content 101 into HDMI content. In such acase, media receiver interface 102 may comprise an HDMI plug and content101 is sent via a wired connection; however, the transfer could occurthrough a wireless connection. In another embodiment, content 101comprises DVI content.

In one embodiment, the transfer of content 101 between media receiverinterface 102 and transmitter device 140 occurs over a wired connection;however, the transfer could occur through a wireless connection.

Transmitter device 140 wirelessly transfers information to receiverdevice 141 using two wireless connections. One of the wirelessconnections is through a phased array antenna with adaptive beamforming,also referred as High Rate Channel. The other wireless connection is viawireless communications channel 107, referred to herein as the Low Ratechannel. In another embodiment, the HR and LR wireless communication areenabled through a MAC, and a PHY (discussed in FIG. 2).

Receiver device 141 transfers the content received from transmitterdevice 140 to media player 114 via media player interface 113. In oneembodiment, the transfer of the content between receiver device 141 andmedia player interface 113 occurs through a wired connection; however,the transfer could occur through a wireless connection. In oneembodiment, media player interface 113 comprises an HDMI plug.Similarly, the transfer of the content between media player interface113 and media player 114 occurs through a wired connection; however, thetransfer could occur through a wireless connection.

Media player 114 causes the content to be played on display 115. In oneembodiment, the content is HDMI content and media player 114 transferthe media content to display via a wired connection; however, thetransfer could occur through a wireless connection. Display 115 maycomprise a plasma display, an LCD, a CRT, etc.

Note that the system in FIG. 1 may be altered to include a DVDplayer/recorder in place of a DVD player/recorder to receive, and playand/or record the content.

In one embodiment, transmitter 140 and media receiver interface 102 arepart of media receiver 100. Similarly, in one embodiment, receiver 141,media player interface 113, and media player 114 are all part of thesame device. In an alternative embodiment, receiver 140, media playerinterface 113, media player 114, and display 115 are all part of thedisplay.

In one embodiment, transmitter device 140 comprises a processor 103, abaseband processing component 104, a phased array antenna 105, and awireless communication channel interface 106. Phased array antenna 105comprises a radio frequency (RF) transmitter having a digitallycontrolled phased array antenna coupled to and controlled by processor103 to transmit content to receiver device 141 using adaptivebeamforming.

In one embodiment, receiver device 141 comprises a processor 112, abaseband processing component 111, a phased array antenna 110, and awireless communication channel interface 109. Phased array antenna 110comprises a radio frequency (RF) transmitter having a digitallycontrolled phased array antenna coupled to and controlled by processor112 to receive content from transmitter device 140 using adaptivebeamforming.

In one embodiment, processor 103 generates signals that are processed bybaseband signal processing 104 prior to being wirelessly transmitted byphased array antenna 105. In such a case, receiver device 141 includesbaseband signal processing to convert analog signals received by phasedarray antenna 110 into baseband signals for processing by processor 112.In one embodiment, the baseband signals are orthogonal frequencydivision multiplex (OFDM) signals. In one embodiment, the basebandsignals are single carrier phase, amplitude, or both phase and amplitudemodulated signals.

In one embodiment, transmitter device 140 and/or receiver device 141 arepart of separate transceivers.

Transmitter device 140 and receiver device 141 perform wirelesscommunication using phased array antenna with adaptive beamforming thatallows beam steering. Beamforming is well known in the art. In oneembodiment, processor 103 sends digital control information to phasedarray antenna 105 to indicate an amount to shift one or more phaseshifters in phased array antenna 105 to steer a beam formed thereby in amanner well-known in the art. Processor 112 uses digital controlinformation as well to control phased array antenna 110. The digitalcontrol information is sent using control channel 121 in transmitterdevice 140 and control channel 122 in receiver device 141. In oneembodiment, the digital control information comprises a set ofcoefficients. In one embodiment, each of processors 103 and 112comprises a digital signal processor.

Wireless communication link interface 106 is coupled to processor 103and provides an interface between wireless communication link 107 andprocessor 103 to communicate antenna information relating to the use ofthe phased array antenna and to communicate information to facilitateplaying the content at another location. In one embodiment, theinformation transferred between transmitter device 140 and receiverdevice 141 to facilitate playing the content includes encryption keyssent from processor 103 to processor 112 of receiver device 141 and oneor more acknowledgments from processor 112 of receiver device 141 toprocessor 103 of transmitter device 140.

Wireless communication link 107 also transfers antenna informationbetween transmitter device 140 and receiver device 141. Duringinitialization of the phased array antennas 105 and 110, wirelesscommunication link 107 transfers information to enable processor 103 toselect a direction for the phased array antenna 105. In one embodiment,the information includes, but is not limited to, antenna locationinformation and performance information corresponding to the antennalocation, such as one or more pairs of data that include the position ofphased array antenna 110 and the signal strength of the channel for thatantenna position. In another embodiment, the information includes, butis not limited to, information sent by processor 112 to processor 103 toenable processor 103 to determine which portions of phased array antenna105 to use to transfer content.

When the phased array antennas 105 and 110 are operating in a modeduring which they may transfer content (e.g., HDMI content), wirelesscommunication link 107 transfers an indication of the status ofcommunication path from the processor 112 of receiver device 141. Theindication of the status of communication comprises an indication fromprocessor 112 that prompts processor 103 to steer the beam in anotherdirection (e.g., to another channel). Such prompting may occur inresponse to interference with transmission of portions of the content.The information may specify one or more alternative channels thatprocessor 103 may use.

In one embodiment, the antenna information comprises information sent byprocessor 112 to specify a location to which receiver device 141 is todirect phased array antenna 110. This may be useful duringinitialization when transmitter device 140 is telling receiver device141 where to position its antenna so that signal quality measurementscan be made to identify the best channels. The position specified may bean exact location or may be a relative location such as, for example,the next location in a predetermined location order being followed bytransmitter device 140 and receiver device 141.

In one embodiment, wireless communications link 107 transfersinformation from receiver device 141 to transmitter device 140specifying antenna characteristics of phased array antenna 110, or viceversa. These antenna characteristics may include phase and/or magnitudevectors used for steering the beam.

FIG. 2 illustrates one embodiment of a communication device 200. Thecommunication device 200 includes data storage 202, an Audio/Video (AV)processor 204, a media access controller (MAC) 206, a physical deviceinterface (PHY) 208, and a radio frequency RF module 210. Data storage202 may store any types of data. For example, data storage 202 may storeaudio and video data as well as other types of data. AV processor 204receives and processes data from data storage 202. MAC 206 handlesgenerating and parsing physical frames. PHY 208 handles how this data isactually moved to/from the radio module 210. As an example, Wireless HDspecification supports two basic types of PHY: high rate PHY (HRP) andlow rate PHY (LRP).

One embodiment of a transceiver is described below. The transceiverincludes transmit and receive paths for a transmitter and receiver,respectively. In one embodiment, the transmitter, for use incommunication with a receiver, comprises a processor and a phased arraybeamforming antenna. The processor controls the antenna to performadaptive beam steering using multiple transmit antennas in conjunctionwith receive antennas of the receiver by iteratively performing a set oftraining operations. One of the training operations comprises theprocessor causing the phased array beamforming antenna to transmit afirst training sequence while a receive antenna-array weight vector ofthe receiver is set and a transmitter antenna-array weight vectorswitches between weight vectors with a set of weight vectors. Another ofthe training operations comprises the processor causing the phased arraybeamforming antenna to transmit a second training sequence while atransmitter antenna-array weight vector is set as part of a process tocalculate the receive antenna-array weight vector.

In one embodiment, the receiver, for use in communication with atransmitter, comprises a processor and a phased array beamformingantenna. The processor controls the antenna to perform adaptive beamsteering using multiple receive antennas in conjunction with transmitantennas of the transmitter by iteratively performing a set of trainingoperations. One of the training operations comprises the processorsetting a receive antenna-array weight vector during a process forestimating a transmit antenna-array weight vector by having thetransmitter transmit a first training sequence while the receiveantenna-array weight vector is set. Another of the training operationscomprises the processor calculate the receive antenna-array weightvector when the transmitter transmits a second training sequence whilethe transmitter antenna-array weight vector is set.

FIGS. 3A and 3B are block diagrams of one embodiment of a transmitterdevice and a receiver device, respectively, that are part of a radiosystem as illustrated in FIG. 1. Transceiver 300 in FIGS. 3A and 3Bincludes multiple independent transmit and receive chains and performsphased array beam forming using a phased array that takes an identicalRF signal and shifts the phase for one or more antenna elements in thearray to achieve beam steering.

Referring to FIG. 3A, digital baseband processing module (e.g., DigitalSignal Processor (DSP)) 301 formats the content and generates real timebaseband signals. Digital baseband processing module 301 may providemodulation, FEC coding, packet assembly, interleaving and automatic gaincontrol.

Digital baseband processing module 301 then forwards the basebandsignals to be modulated and sent out on the RF portion of thetransmitter. In one embodiment, the content is modulated into OFDMsignals in a manner well known in the art.

Digital-to-analog converter (DAC) 302 receives the digital signalsoutput from digital baseband processing module 301 and converts them toanalog signals. In one embodiment, the signal outputs from DAC 302 arebetween 0-1.7 GHz. Analog-front end 303 receives the analog signals andfilters it with an appropriate low-pass image-rejection filter andamplifies it accordingly.

In one embodiment, an IF mixer module 326 receives the output signal ofanalog front end 303. The IF mixer module 326 is configured to generatea fixed intermediate frequency to RF mixer 305. As an example, IF mixermodule 326 includes an IF mixer 321 and an IF module 304. In oneembodiment, IF module 304 includes a bandpass filter. In anotherembodiment, IF module 304 includes an IF tuned amplifier. IF mixer 321receives the output of analog front end 303 and a single frequencysynthesizer 322 and up-converts it to the IF frequency. IF module 304receives the output of IF mixer 321. Those of ordinary skills in the artwill recognize that other components may be used to perform similarfunctions of IF mixer module 326. For example, the IF mixer module 326may include an IF filter.

In one embodiment, the generation circuit as presently describedincludes only one single frequency synthesizer 322 with an oscillatingfrequency of 12.96 GHz.

A programmable divider 323 and a single side band mixer 324 receive theoutput of the single frequency synthesizer 322. In one embodiment,programmable divider 323 divides with multiple of two (e.g. 8, 12, 24).Single side band mixer 324 also receives the output of programmabledivider 323. In one embodiment, single side band mixer 324 outputs thefollowing frequencies: 11.34 GHz, 11.88 GHz, 12.42 GHz, and 12.96 GHz.

A quadrupler 325 receives the output of single side band mixer 324.Those of ordinary skills in the art will recognize that quadrupler 325may includes different components when combined perform the samefunction. For example, quadrupler 325 can include two frequencydoublers. The quadrupler 325 is described here as an example. In anotherembodiment, a frequency multiplier may be used. The frequency multipliermay include a quadrupler or a doubler.

One embodiment of coupling a mixer with a frequency multiplier is tocouple a sub-harmonic mixer with a frequency multiplier at a lowermultiplication factor or to just use a sub-harmonic mixer.

RF mixer 305 receives signals output from IF mixer module 326 andcombines them with the signal from quadrupler 325. The signals outputfrom RF mixer 305 are at a radio frequency. In one embodiment, the radiofrequency of the signal output of RF mixer 305 is 58.32 GHz, 60.48 GHz,62.64 GHz, and 64.8 GHz.

Multiplexer 306 is coupled to receive the output from RF mixer 305 tocontrol which phase shifters 307 _(1-N) receive the signals. In oneembodiment, phase shifters 307 _(1-N) are quantized phase shifters. Inan alternative embodiment, phase shifters 307 _(1-N) may be replaced byIF or RF amplifiers with controllable gain and phase. In one embodiment,digital baseband processing module 201 also controls, via controlchannel 360, the phase and magnitude of the currents in each of theantenna elements in phased array antenna to produce a desired beampattern in a manner well-known in the art. In other words, digitalbaseband processing module 201 controls the phase shifters 307 _(1-N) ofphased array antenna to produce the desired pattern.

Each of phase shifters 307 _(1-N) produce an output that is sent to oneof power amplifiers 308 _(1-N), which amplify the signal. The amplifiedsignals are sent to an antenna array that has multiple antenna elements309 _(1-N). In one embodiment, the signals transmitted from antennas 309_(1-N) are radio frequency signals between 56-64 GHz. In one embodiment,the radio frequency signals center at 58.32 GHz, 60.48 GHz, 62.64 GHz,and 64.8 GHz. Thus, multiple beams are output from the phased arrayantenna.

With respect to the receiver in FIG. 3B, antennas 310 _(1-K) receive thewireless transmissions from antennas 309 _(1-N) and provide them tophase shifters 312 _(1-K), via low-noise amplifiers 311 _(1-N),respectively. As discussed above, in one embodiment, phase shifters 312_(1-K) comprise quantitized phase shifters. Alternatively, phaseshifters 312 _(1-K) may be replaced by complex multipliers. Phaseshifters 312 _(1-N) receive the signals from antennas 310 _(1-K), whichare combined by RF combiner 313 to form a single line feed output. Inone embodiment, a multiplexer is used to combine the signals from thedifferent elements and output the single feed line. RF Mixer 314receives the output of RF combiner 313.

RF Mixer 314 receives the output signal of RF combiner 313 and combinesit with a signal from frequency quadrupler 325. In one embodiment, theoutput of RF mixer 314 is an IF signal that a IF mixer module 326down-converts to the baseband frequency. In one embodiment, the radiofrequency of input signal to RF mixer 314 centers at 58.32 GHz, 60.48GHz, 62.64 GHz, or 64.8 GHz.

In one embodiment, frequency quadrupler 325 receives the output of mixer324 at one of the frequencies of 11.34 GHz, 11.88 GHz, 12.42 GHz, 12.96GHz. Mixer 324 receives the output of a programmable divider 323 andsingle synthesizer 322 operating at 12.96 GHz. Single synthesizer 322also generates an output signal to IF mixer module 326.

In one embodiment, IF mixer module 326 includes an IF module 315 and anIF mixer 321. In one embodiment, IF module 315 includes a bandpassfilter. In another embodiment, IF module 315 includes an IF tunedamplifier. Analog front end 316 receives the output signal of IF mixermodule 326.

Analog-to-digital converter (ADC) 317 receives the output of analogfront end 316 and converts it to digital form. The digital output fromADC 317 is received by digital baseband processing module (e.g., DSP)318. Digital baseband processing module 318 restores the amplitude andphase of the signal. Digital baseband processing module 318 may providedemodulation, packet disassembly, de-interleaving and automatic gain.

In one embodiment, each of the transceivers includes a controllingmicroprocessor that sets up control information for the digital basebandprocessing module (e.g., DSP). The controlling microprocessor may be onthe same die as the digital baseband processing module (e.g., DSP).

DSP-Controlled Adaptive Beam Forming

In one embodiment, the DSPs implement an adaptive algorithm with thebeam forming weights being implemented in hardware. That is, thetransmitter and receiver work together to perform the beam forming in RFfrequency using digitally controlled analog phase shifters; however, inan alternative embodiment, the beam-forming is performed in IF. Phaseshifters 307 _(1-N) and 312 _(1-N) are controlled via control channel360 and control channel 370, respectfully, via their respective DSPs ina manner well known in the art. For example, digital baseband processingmodule (e.g., DSP) 301 controls phase shifters 307 _(1-N) to have thetransmitter perform adaptive beam-forming to steer the beam whiledigital baseband processing module (e.g., DSP) 318 controls phaseshifters 312 _(1-N) to direct antenna elements to receive the wirelesstransmission from antenna elements and combine the signals fromdifferent elements to form a single line feed output. In one embodiment,a multiplexer is used to combine the signals from the different elementsand output the single feed line. Note that processors (e.g., DSPs) thatcontrol the digital baseband processing modules, such as shown in thetransmitters and receivers of FIG. 1, could be coupled to controlchannels 360 and 370, respectively, could be used to control phaseshifters 307 _(1-N) and 312 _(1-N).

Digital baseband processing module (e.g., DSP) 301 performs the beamsteering by pulsing, or energizing, the appropriate phase shifterconnected to each antenna element. The pulsing algorithm under digitalbaseband processing module (e.g., DSP) 301 controls the phase and gainof each element. Performing DSP controlled phase array beam-forming iswell known in the art.

The adaptive beam forming antenna is used to avoid interferingobstructions. By adapting the beam forming and steering the beam, thecommunication can occur avoiding obstructions which may prevent orinterfere with the wireless transmissions between the transmitter andthe receiver.

In one embodiment, with respect to the adaptive beam-forming antennas,they have three phases of operations. The three phases of operations arethe training phase, a searching phase, and a tracking phase. Thetraining phase and searching phase occur during initialization. Thetraining phase determines the channel profile with predeterminedsequences of spatial patterns {Aî} and {Bĵ}. The searching phasecomputes a list of candidate spatial patterns {Aī}, {B j} and selects aprime candidate {A 0 , B 0 } for use in the data transmission betweenthe transmitter of one transceiver and the receiver of another. Thetracking phase keeps track of the strength of the candidate list. Whenthe prime candidate is obstructed, the next pair of spatial patterns isselected for use.

In one embodiment, during the training phase, the transmitter sends outa sequence of spatial patterns {Aî}. For each spatial pattern {Aî}, thereceiver projects the received signal onto another sequence of patterns{Bĵ}. As a result of the projection, a channel profile is obtained overthe pair {Aî}, {Bĵ}.

In one embodiment, an exhaustive training is performed between thetransmitter and the receiver in which the antenna of the receiver ispositioned at all locations and the transmitter sending multiple spatialpatterns. Exhaustive training is well-known in the art. In this case, Mtransmit spatial patterns are transmitted by the transmitter and Nreceived spatial patterns are received by the receiver to form an N by Mchannel matrix. Thus, the transmitter goes through a pattern of transmitsectors and the receiver searches to find the strongest signal for thattransmission. Then the transmitter moves to the next sector. At the endof the exhaustive search process, a ranking of all the positions of thetransmitter and the receiver and the signals strengths of the channel atthose positions has been obtained. The information is maintained aspairs of positions of where the antennas are pointed and signalstrengths of the channels. The list may be used to steer the antennabeam in case of interference.

In an alternative embodiment, subspace training is used in which thespace is divided in successively narrow sections with orthogonal antennapatterns being sent to obtain a channel profile.

Assuming digital baseband processing module 301 (DSP) is in a stablestate and the direction the antenna should point is already determined.In the nominal state, the DSP will have a set of coefficients that itsends to the phase shifters. The coefficients indicate the amount ofphase the phase shifter is to shift the signal for its correspondingantennas. For example, digital baseband processing module 301 (DSP)sends a set digital control information to the phase shifters thatindicate the different phase shifters are to shift different amounts,e.g., shift 30 degrees, shift 45 degrees, shift 90 degrees, shift 180degrees, etc. Thus, the signal that goes to that antenna element will beshifted by a certain number of degrees of phase. The end result ofshifting, for example, 16, 32, 36, 64 elements in the array by differentamounts enables the antenna to be steered in a direction that providesthe most sensitive reception location for the receiving antenna. Thatis, the composite set of shifts over the entire antenna array providesthe ability to stir where the most sensitive point of the antenna ispointing over the hemisphere.

Note that in one embodiment the appropriate connection between thetransmitter and the receiver may not be a direct path from thetransmitter to the receiver. For example, the most appropriate path maybe to bounce off the ceiling.

The Back Channel

In one embodiment, the wireless communication system includes a backchannel 320, or link, for transmitting information between wirelesscommunication devices (e.g., a transmitter and receiver, a pair oftransceivers, etc.). The information is related to the beam-formingantennas and enables one or both of the wireless communication devicesto adapt the array of antenna elements to better direct the antennaelements of a transmitter to the antenna elements of the receivingdevice together. The information also includes information to facilitatethe use of the content being wirelessly transferred between the antennaelements of the transmitter and the receiver.

In FIGS. 3A and 3B, back channel 320 is coupled between digital basebandprocessing module (DSP) 318 and digital baseband processing module (DSP)301 to enable digital baseband processing module (DSP) 318 to sendtracking and control information to digital baseband processing module(DSP) 301. In one embodiment, back channel 320 functions as a high speeddownlink and an acknowledgement channel.

In one embodiment, the back channel is also used to transfer informationcorresponding to the application for which the wireless communication isoccurring (e.g., wireless video). Such information includes contentprotection information. For example, in one embodiment, the back channelis used to transfer encryption information (e.g., encryption keys andacknowledgements of encryption keys) when the transceivers aretransferring HDMI data. In such a case, the back channel is used forcontent protection communications.

More specifically, in HDMI, encryption is used to validate that the datasink is a permitted device (e.g., a permitted display). There is acontinuous stream of new encryption keys that is transferred whiletransferring the HDMI datastream to validate that the permitted devicehasn't changed. Blocks of frames for the HD TV data are encrypted withdifferent keys and then those keys have to be acknowledged back on backchannel 320 in order to validate the player. Back channel 220 transfersthe encryption keys in the forward direction to the receiver andacknowledgements of key receipts from the receiver in the returndirection. Thus, encrypted information is sent in both directions.

The use of the back channel for content protection communications isbeneficial because it avoids having to complete a lengthy retrainingprocess when such communications are sent along with content. Forexample, if a key from a transmitter is sent alongside the contentflowing across the primary link and that primary link breaks, it willforce a lengthy retrain of 2-3 seconds for a typical HDMI/HDCP system.In one embodiment, this separate bi-directional link that has higherreliability than the primary directional link given its omni-directionalorientation. By using this back channel for communication of the HDCPkeys and the appropriate acknowledgement back from the receiving device,the time consuming retraining can be avoided even in the event of themost impactful obstruction.

In the active mode, when the beam-forming antennas are transferringcontent, the back channel is used to allow the receiver to notify thetransmitter about the status of the channel. For example, while thechannel between the beam-forming antennas is of sufficient quality, thereceiver sends information over the back channel to indicate that thechannel is acceptable. The back channel may also be used by the receiverto send the transmitter quantifiable information indicating the qualityof the channel being used. If some form of interference (e.g., anobstruction) occurs that degrades the quality of the channel below anacceptable level or prevents transmissions completely between thebeam-forming antennas, the receiver can indicate that the channel is nolonger acceptable and/or can request a change in the channel over theback channel. The receiver may request a change to the next channel in apredetermined set of channels or may specify a specific channel for thetransmitter to use.

In one embodiment, the back channel is bi-directional. In such a case,in one embodiment, the transmitter uses the back channel to sendinformation to the receiver. Such information may include informationthat instructs the receiver to position its antenna elements atdifferent fixed locations that the transmitter would scan duringinitialization. The transmitter may specify this by specificallydesignating the location or by indicating that the receiver shouldproceed to the next location designated in a predetermined order or listthrough which both the transmitter and receiver are proceeding.

In one embodiment, the back channel is used by either or both of thetransmitter and the receiver to notify the other of specific antennacharacterization information. For example, the antenna characterizationinformation may specify that the antenna is capable of a resolution downto 6 degrees of radius and that the antenna has a certain number ofelements (e.g., 32 elements, 64 elements, etc.).

In one embodiment, communication on the back channel is performedwirelessly by using interface units. Any form of wireless communicationmay be used. In one embodiment, OFDM is used to transfer informationover the back channel. In another embodiment, CPM is used to transferinformation over the back channel.

FIG. 4 illustrates one embodiment of frequency channel plot resultingfrom the generation circuit previously described. Channel 1 operates atabout 58.32 GHz. Channel 2 operates at about 60.48 GHz. Channel 3operates at about 62.64 GHz. Channel 4 operates at about 64.80 GHz.

In the description, numerous details are set forth to provide a morethorough explanation of the present invention. It will be apparent,however, to one skilled in the art, that the present invention may bepracticed without these specific details. In other instances, well-knownstructures and devices are shown in block diagram form, rather than indetail, in order to avoid obscuring the present invention.

Some portions of the detailed descriptions which follow are presented interms of algorithms and symbolic representations of operations on databits within a computer memory. These algorithmic descriptions andrepresentations are the means used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of steps leading to a desiredresult. The steps are those requiring physical manipulations of physicalquantities. Usually, though not necessarily, these quantities take theform of electrical or magnetic signals capable of being stored,transferred, combined, compared, and otherwise manipulated. It hasproven convenient at times, principally for reasons of common usage, torefer to these signals as bits, values, elements, symbols, characters,terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the following discussion,it is appreciated that throughout the description, discussions utilizingterms such as “processing” or “computing” or “calculating” or“determining” or “displaying” or the like, refer to the action andprocesses of a computer system, or similar electronic computing device,that manipulates and transforms data represented as physical(electronic) quantities within the computer system's registers andmemories into other data similarly represented as physical quantitieswithin the computer system memories or registers or other suchinformation storage, transmission or display devices.

The present invention also relates to an apparatus for performing theoperations herein. This apparatus may be specially constructed for therequired purposes, or it may comprise a general purpose computerselectively activated or reconfigured by a computer program stored inthe computer. Such a computer program may be stored in a computerreadable storage medium, such as, but is not limited to, any type ofdisk including floppy disks, optical disks, CD-ROMs, andmagnetic-optical disks, read-only memories (ROMs), random accessmemories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any typeof media suitable for storing electronic instructions, and each coupledto a computer system bus.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems may be used with programs in accordance with the teachingsherein, or it may prove convenient to construct more specializedapparatus to perform the required method steps. The required structurefor a variety of these systems will appear from the description below.In addition, the present invention is not described with reference toany particular programming language. It will be appreciated that avariety of programming languages may be used to implement the teachingsof the invention as described herein.

A machine-readable medium includes any mechanism for storing ortransmitting information in a form readable by a machine (e.g., acomputer). For example, a machine-readable medium includes read onlymemory (“ROM”); random access memory (“RAM”); magnetic disk storagemedia; optical storage media; flash memory devices; electrical, optical,acoustical or other form of propagated signals (e.g., carrier waves,infrared signals, digital signals, etc.); etc.

Whereas many alterations and modifications of the present invention willno doubt become apparent to a person of ordinary skill in the art afterhaving read the foregoing description, it is to be understood that anyparticular embodiment shown and described by way of illustration is inno way intended to be considered limiting. Therefore, references todetails of various embodiments are not intended to limit the scope ofthe claims which in themselves recite only those features regarded asessential to the invention.

1. A device comprising: a single synthesizer; a frequency dividercoupled to the single synthesizer; a mixer coupled to the singlesynthesizer and to the frequency divider; a frequency quadruplet coupledto the mixer; and a radio frequency (RF) mixer coupled to the frequencyquadrupler.
 2. The device of claim 1 further comprising: an IF mixermodule coupled to the single synthesizer.
 3. The device of claim 2wherein the IF mixer module comprises an IF mixer and an IF module. 4.The device of claim 2 wherein the IF mixer module comprises an IFfilter.
 5. The device of claim 1 wherein the RF mixer is operable togenerate frequency outputs of 58.32 GHz, 60.48 GHz, 62.64 GHz, and 64.8GHz with a fixed intermediate frequency.
 6. The device of claim 1wherein the single synthesizer operates at a frequency of about 12.96GHz.
 7. The device of claim 1 wherein the frequency divider has adivider ratio that is a multiple of two.
 8. The device of claim 6wherein the frequency divider is configured to divide by 8, 12, or 24.9. The device of claim 1 wherein the frequency quadrupler comprises twofrequency doublers.
 10. The device of claim 1 wherein the mixer includesa single side band mixer.
 11. The device of claim 2 further comprising:a processor configured to generate baseband signals; a digital-to-analogconverter (DAC) coupled to the processor to convert the baseband signalsto analog signals; and an analog front end coupled to the DAC to filterand amplify the analog signals, the IF mixer module to receive an outputof the analog front end.
 12. The device of claim 11 further comprising:a multiplexer coupled to the RF mixer; and a plurality of phase shifterscoupled to the multiplexer, the multiplexer to control which phaseshifter is to receive a signal.
 13. The device of claim 12 furthercomprising: a plurality of power amplifiers coupled to the plurality ofphase shifters; and a plurality of antennas coupled to the plurality ofpower amplifiers.
 14. The device of claim 12 further comprising: acontrol channel to couple the processor to the plurality of phaseshifters, the processor to control via the control channel the phase andmagnitude of currents in each of the antennas to produce a desired beampattern.
 15. The device of claim 2 further comprising: an analog frontend to receive an output of the IF mixer module to convert an IF signalto a baseband frequency signal; an analog-to-digital converter (ADC)coupled to the analog front end to convert the baseband frequency signalto a digital signal; and a processor coupled to the ADC to restore anamplitude and a phase of the digital signal.
 16. The device of claim 15further comprising: a RF combiner coupled to the RF mixer, the RF mixerconfigured to generate a fixed IF frequency from multiple frequenciesreceived from the RF combiner; and a plurality of phase shifters coupledto the RF combiner, the RF combiner to form a single line feed output.17. The device of claim 16 further comprising: a plurality of amplifierscoupled to the plurality of phase shifters; and a plurality of antennascoupled to the plurality of amplifiers.
 18. The device of claim 16further comprising: a control channel to couple the processor to theplurality of phase shifters, the processor to control via the controlchannel the phase and magnitude of currents in each of the antennas toreceive a desired beam pattern.
 19. A device comprising: a processor; aradio frequency (RF) transmitter coupled to and controlled by theprocessor to generate frequency outputs at 58.32 GHz, 60.48 GHz, 62.64GHz, and 64.8 GHz.
 20. The device of claim 19 wherein the RF transmitterfurther comprises: an IF mixer module; a single synthesizer coupled tothe IF mixer module; a frequency divider coupled to the singlesynthesizer; a single side band mixer coupled to the single synthesizerand to the frequency divider; and a frequency quadrupler coupled to anRF mixer, the RF mixer coupled to the IF mixer module.
 21. The device ofclaim 20 wherein the single synthesizer operates at a frequency of about12.96 GHz.
 22. The device of claim 21 wherein the frequency divider isconfigured to divide by 8, 12, or
 24. 23. The device of claim 19 whereinthe RF mixer is configured to generate multiple RF frequencies with afixed intermediate frequency.
 24. The device of claim 19 wherein the RFmixer is configured to generate a fixed intermediate frequency withmultiple RF frequencies.
 25. The device of claim 19 wherein the deviceis used for a wireless video area network (WVAN).
 26. The device ofclaim 19 wherein the device is used for a wireless personal area network(WPAN).
 27. The device of claim 19 wherein the device is used for awireless local area network (WLAN).
 28. A device comprising: a singlesynthesizer; a frequency divider coupled to the single synthesizer; amixer coupled to the single synthesizer and to the frequency divider; afrequency multiplier coupled to the mixer; and a radio frequency (RF)mixer coupled to the frequency multiplier;
 29. The device of claim 28wherein the frequency multiplier comprises a quadrupler.
 30. The deviceof claim 28 wherein the frequency multiplier comprises a doubler.